Abstract
Purpose: :
The exact etiology of AMD is unknown but is believed to involve interaction of genetic and environmental factors. The most consistent risk factors associated with AMD are increasing age and cigarette smoking. Besides, oxidative stress might also have an important role. The purpose of this study was to investigate any possible relationship between AMD and other environmental factors, such as trace elements, by measuring levels of trace elements in the aqueous humor in eyes with and without AMD.
Methods: :
For this prospective cohort study, aqueous humour samples were collected from patients undergoing cataract surgery. 15 patients with dry AMD (Age 79.6±5.2, female 10, male 5) and 15 patients without AMD (Age 70.6±4.2, female 8, male 7) were included.Cadmium, cobalt, copper, iron, and zinc were measured by using the technique of Inductively-Coupled-Plasma-Mass-Spectrometry (ICP-MS) and Certified Biological Standards. Non-parametric testing (Mann-Whitney U) was performed. All statistical tests were two-sided and the significance level was set at α = 0.05 after Bonferoni correction.
Results: :
A number of trace elements were detected and measured in all aqueous humour samples of patients with and without AMD. Statistical analysis with t-tests showed that patients with AMD had significantly higher levels of cadmium (0.95 ± 1.1 µmol/L vs. 0.12 ± 0.16 µmol/L; p < 0.001), cobalt (2.99 ± 0.6 µmol/L vs. 1.15 ± 0.24 µmol/L; p < 0.001), iron (305.1 ± 37.52 µmol/L vs. 131.25 ± 25.96 µmol/L; p < 0.001), and zinc (24.17 ± 15.92 µmol/L vs. 6.78 ± 4.32 µmol/L; p < 0.01) than control subjects without AMD. Copper level was significantly reduced in patients with AMD (30.71 ± 39.16 µmol/L vs. 107.93 ± 133.51 µmol/L; p < 0.001).
Conclusions: :
The findings for cadmium and copper support the role of established environmental risk factors, for AMD. The higher levels of zinc in the aqueous humor of patients with AMD are in contrast to other studies. In addition, the result for iron is in line with some evidence that iron accumulation may be a risk factor in AMD by generating oxygen free radicals through the Fenton reaction.
Keywords: age-related macular degeneration • anterior chamber • aqueous